Mataura over-allocation frequently asked questions

There are a number of reasons that have contributed to the over-allocation. Pattle Delamore Partners (PDP), an environmental and engineering consultancy, were contracted to carry out an independent review into the over-allocation. This did not find any errors in the decisions on previous consent applications based on the information that was provided to decision makers at the time. Their review states that over-allocation has occurred because:

• Some consents, that affect the flow in the river, had been omitted from previous allocation totals;
• The effect of some groundwater takes on the river flow had not been properly assessed;
• Implementation of the stream depletion calculation methods in the proposed Southland Water and Land Plan have increased the overall quantity that needs to be included in the surface water allocation bands.

Further information can be found in the PDP report, which can be found at https://www.es.govt.nz/environment/water/MatauraWCO

The over-allocation only affects that part of the catchment upstream of Gore. Abstractions downstream of Gore are not affected.

We estimate 56 consents are affected by the over-allocation. There are some consent holders who have more than one consent that is affected.

The WCO applies to most, but not all, of the Mataura River catchment. The protected waters under the WCO are:

• The Mataura River from its source to the sea
• The Waikaia River and its tributaries, the Otamita Stream, and all other tributaries of the Mataura River upstream of its confluence with the Otamita Stream
• The Mimihau Stream and the Mokoreta River and each of their tributaries.

The Mataura WCO stipulates that at any point above the Mataura Island Road Bridge, 95% of the natural flow in the Mataura River and protected tributaries must remain. As a regional council, we are required to adhere to the order when issuing consents for water takes and the WCO prohibits us from issuing any new or replacement resource consents if more than 95% of the flow is allocated for abstraction. There are key measuring points within the catchment, with the upstream measuring point at Gore being over-allocated.

The Council manages the allocation under the WCO by allocating water using a band system. The river flow is divided into minimum flow bands, with 5% of the flow in each band allocated for water abstraction (allowing 95% to remain in the river). The first band is below 9 cubic meters per second (cumecs) at Gore, with minimum flow cut-offs progressively increased at two cumec blocks at Gore e.g. 11, 13, 15, 17, 19, 21, 23 cumecs. Allocating 5% of the flow means that 450 litres per second (l/s) can be allocated below 9 cumecs (being 5% of 9 cumecs), 550 l/s below 11 cumecs and so on.

The consent review is solely to address the over-allocation under the Mataura Water Conservation Order. It will not deal with any other matters.

It is too early to determine this and we hope to work with consent holders in a collaborative manner to find a solution to the over-allocation. The solution may include a mix of things such as: reviews of stream depletion calculations, reductions in rates of take to better reflect actual use, some movement of consents to higher bands, and/or the introduction of water use groups to the catchment.

Previous experience throughout the country tells us that we are best to find a solution to the over-allocation by working together and endeavouring to avoid involvement from the Courts. If the over-allocation is resolved through the Courts, the process is likely to take longer, cost the parties considerably more, and have a less certain outcome. While we are open to working with consent holders as individuals, we consider that there are a number of efficiencies that can be gained from consent holders working as a group or groups.

We acknowledge that this issue is not ideal and will take some work to resolve. After working through options for solutions, this will need to be formalised through a consent review process. All resource consents have a condition which provides for a consent review notice to be issued between May and September (or similar) each year. Our aim is to serve notices of review between May and September 2022 to address the over-allocation. If, for some reason, more time is required for solution options to be worked through with affected consent holders, this could be delayed to the same period in 2023. However, this will require additional consent renewals to be put on hold and have an impact on those consent holders wanting to make decisions about the development of their property.

This will depend on the solution to the over-allocation. You may have a slight reduction in water availability, for example if you move to a higher minimum flow cut-off band, or your rate of take may be reduced.

The cost will be met by Environment Southland, however, if a consent holder decides to engage a consultant to assist them with the process then they will have to pay for the consultant’s costs.

Yes, the over-allocation can be resolved. This is consistent with the interim decision of the Environment Court on this appeal, which requires that the parties report to the Court on progress to resolve the over-allocation by 21 September 2022.

Resource consents to take groundwater that have a riparian, direct, high, or moderate connection to a surface waterway that is protected by the Mataura WCO are included in the allocation. This is determined by the proposed Southland Water and Land Plan and is also consistent with the operative Regional Water Plan. For these consents, it is the portion of the abstraction that is calculated to come from a river or stream (the stream depletion) that is included in the allocation, rather than the full rate of take authorised by the consent.

When groundwater abstraction occurs in the vicinity of a surface waterway it can cause a reduction in the flow in that waterway. This is a process known as stream depletion. The magnitude of the flow reduction depends on the hydraulic connection between the groundwater and the surface waterway. The calculated effect is determined from:

• The groundwater pumping rates authorised by consents, as described above;
• Parameters that describe the flow of water through the aquifer when the bore is pumped;
• Parameters that describe the hydraulic connection between the surface waterway and the aquifer.

The management of stream depletion is undertaken in accordance with the methodology described in Appendix L.2 of the proposed Southland Water and Land Plan. This classifies the hydraulic connection between a bore and a surface waterway as either riparian, direct, high, moderate or low. Groundwater abstractions that are classified as riparian, direct, high or moderate are incorporated into the surface water management regime that is subject to the Mataura WCO.

Yes, both the proposed and operative plans required that moderately connected groundwater takes are included in the allocation where the magnitude of connection exceeds twolitres per second. No specific minimum flow conditions are required for moderately connected groundwater takes, unlike takes with a high or direct connection.

It is Environment Southland’s view that the only way to remove moderately connected takes from the allocation would be through a change to the regional plan. This would likely be a time-consuming process that would receive opposition from other groups and have an uncertain outcome.

Please contact our project manager Bianca Sullivan on bianca.sullivan@es.govt.nz or 021 057 4794.